T-Mobile (Germany) MultiSIM Mailbox issue

I have been having issues with my Fujitsu U772 Lifebook (Sierra Wireless MC8305 & MC7710) and the MultiSIM from T-Mobile Germany (=same number, 2 SIM cards). The Problem is, that as soon as I log in via my Laptop it seems to send an information to my operator that i can not recieve calls with this Setup and therefore my Mailbox is activated permanently. The only way to solve this Problem is to shut down my laptop, remove the SIM card and then reactivate my mailbox only when I don’t answer the call (means 30sec ringing and then mailbox).
I have spoken with my operator and all they could do was say “buy a new laptop which supports this feature or set up a new phone number for 30€/month”, which is definately not an option…
Please help me! I like my little laptop and can’t believe that there is no solution for this problem :wink:
Please excuse my bad english - I have left school a long time ago :slight_smile:

nobody? :frowning:


I did not get the USE case correctly…
What i believe is you want to use both the sim cards simultaneously, but having issues with the mailbox.
Now, what mailbox you are referring to here? SMS or some mail transfer kind of thing?

What i understood is that you are not allowed to receive calls while using the SIM card and in your fujitsu…
so, one thing is clear :
one sim card is there in the SIM slot of fujitsu and where’s the other one?

It seems to be network dependent, if you want to use 2 sim cards with the same number.

Look at this :


thanks for your reply.
the way i use this option: i have an iPhone with which i do calls, sms, and very little surfing/mails. since my provider offers exactly the option you have linked for free i want to use the second card in my laptop ONLY for surfing.

the issue seems to be that as soon as the laptop connects to the network it sends a code to my provider telling him to block all calls probably because the device is not capable of doing so. (GSM Codes: t-mobile.de/downloads/steuer … 4-2013.pdf )
as soon as this has happened i will NOT recieve any calls to my phone until i reboot laptop AND phone. after that i have to send a gsm code to reactivate my phone.

wierd thing is that i can make calls, text and surf from my phone whilst having an active connection with the laptop.



as soon as you connect your laptop with other SIM card, the call/sms facility is not there on your cell phone… right??

does The same issue appears if you first connect to the laptop with a SIM card and then connect the SIM card to your phone???

“wierd thing is that i can make calls, text and surf from my phone whilst having an active connection with the laptop” … just now u told that u were not able to make any calls from your phone once you connect the SIM to your laptop… a bit of ambiguity…

But, yes… it is a network issue… i am not much sure… but it seems that the network provider has to enable simultaneous access to both the SIM even if one of the device doesn’t support calls facility… and ofcourse for that u have to pay some bucks for that…

Will try to find information about this…
Cannot even reproduce this as my network doesn’t support multi sim with same number :frowning:

Will get back to you on this sure!


we seem to have a misunderstandig here. i can at all times make calls with my mobile phone, the issue is that i do not recieve any once i have booked into the network with the laptop.

i have colleagues with the same “multi sim option” but they don’t work with a laptop. instead they use iPhone for calls/sms/web and an iPad for surfing and they don’t face the issues i have. this means to me, it is not something that has to do with the network provider but rather with the device that is booking in. please correct me if i am wrong…

thanks again!

does it work now?